3g CIRCULAR 491, U. S. DEPARTMENT OF AGRICULTURE 



Plains, although they have given satisfactory results where the an- 

 nual precipitation approaches or exceeds 30 inches. Repeating a 

 report issued in 1894, Griffin (29) states that these grasses were not 

 successful in the Arkansas River Valley in Colorado. Getty (27) 

 also reported consistent failure with these species at Hays, Kans. 



SUPPLEMENTARY INFORMATION 



Additional information concerning the distribution of native 

 plants species is reported by Gates (2 J/.) for Kansas; Cory and Parks 

 (19) for Texas; and the Division of Forage Crops and Diseases, 

 Bureau of Plant Industry, 7 for 11 locations in the central and southern 

 Great Plains. Parks (50) lists and describes native plants of economic 

 value in Texas, and Cory (18) shows the preference of livestock for 

 different classes of range forage. 



GRASS MIXTURES 



Seeding a mixture of well-adapted species may result in the fol- 

 lowing advantages over seedings in pure cultures: More success in 

 obtaining a stand, a greater variety of forage, a longer grazing pe- 

 riod by the use of early and late strains, more rapid and complete 

 occupancy of the land by the use of vegetative-spreading species in 

 conjunction with those capable of spreading solely by seed, and rapid 

 growth of some species while others are slowly becoming established. 

 Seeding mixtures of blue grama and bluestem (western wheatgrass) 

 in combination with wide-spaced sodding of buffalo grass offers prom- 

 ising possibilities for medium heavy to heavy soils. 



EFFECT OF SOURCE OF SEED 



One of the most remarkable revelations of recent testing work with 

 native grasses is the effect of source of seed on growth. Seeds of 

 many species have been obtained from southern Texas and Arizona 

 and from various locations successfully farther north into Montana 

 and North Dakota. When grown at Woodward, Okla., the plants 

 from the most southern locations were decidedly later in flowering 

 but noticeably taller, more vigorous, and produced much more forage 

 than those grown from seed harvested farther north (fig. 19). The 

 growth was successively less and the plants earlier in maturity with 

 each successive northerly acquisition. These results indicate that 

 it is not advisable to use seed from the North if well-adapted local 

 seed is available. They further indicate the possibility of improve- 

 ment by introducing seed from southern locations, if weaknesses such 

 as susceptibility to drought and cold are not also introduced. 



REJUVENATING DEPLETED PASTURES 



Native grasslands of the central and southern Great Plains have 

 become seriously depleted in stand, vigor, and carrying capacity as 

 a result of prolonged drought, intense heat, and soil blowing, com- 



Savage, D. A. See footnote 3, p. 2. 



